Scientists at University College London have identified a biological mechanism that helps the body turn off inflammation once it's no longer needed, potentially reshaping how we treat chronic pain and inflammatory diseases. The discovery centers on fat-derived molecules called epoxy-oxylipins, which act as natural brakes on the immune system. In a carefully controlled human study, researchers found that boosting these protective molecules reduced pain faster and significantly lowered the harmful immune cells linked to chronic inflammation .

How Do These Fat Molecules Actually Work?

Inflammation is your body's natural defense against infection and injury. But when it persists unchecked, it can drive chronic conditions like arthritis, heart disease, and diabetes. Until now, scientists didn't fully understand how the body transitions from an active immune response to a healing phase. The new research, published in Nature Communications, reveals that epoxy-oxylipins prevent the buildup of specific immune cells called intermediate monocytes, which fuel chronic inflammation when they accumulate .

To test this process in humans, researchers conducted an experiment with 48 healthy volunteers. They injected UV-killed E. coli bacteria into participants' forearms to trigger a temporary inflammatory response similar to what happens after infection or injury. Half the group received a drug called GSK2256294, which blocks an enzyme that normally breaks down epoxy-oxylipins, effectively boosting these protective molecules. The other half received a placebo .

The results were striking. Participants who received the drug experienced faster pain resolution and had significantly lower levels of intermediate monocytes in both their blood and tissue. Notably, the medication didn't meaningfully change visible symptoms like redness or swelling, suggesting it works by calming the immune system at a deeper level rather than just masking surface inflammation .

What Conditions Could Benefit From This Discovery?

The implications extend far beyond the laboratory. Researchers identified that one specific epoxy-oxylipin, called 12,13-EpOME, works by suppressing a protein signaling pathway known as p38 MAPK, which drives the transformation of monocytes into inflammatory cells. This understanding opens the door to developing safer treatments for diseases driven by chronic inflammation .

The study was funded by Arthritis UK and involved researchers from multiple institutions, including King's College London, University of Oxford, Queen Mary University of London, and the National Institute of Environmental Health Sciences. The findings suggest potential clinical applications for several conditions:

• Rheumatoid Arthritis: A condition where the immune system attacks cells lining the joints; sEH inhibitors (soluble epoxide hydrolase inhibitors) could potentially prevent or slow joint damage when used alongside existing medications.
• Cardiovascular Disease: Chronic inflammation plays a major role in heart disease; boosting epoxy-oxylipins could help reduce inflammatory damage to blood vessels and heart tissue.
• Other Inflammatory Conditions: Any disease driven by persistent immune activation could potentially benefit from treatments that enhance the body's natural inflammation-shutoff mechanism.

Dr. Olivia Bracken, the study's first author from UCL's Department of Ageing, Rheumatology and Regenerative Medicine, explained the significance of the finding. "Our findings reveal a natural pathway that limits harmful immune cell expansion and helps calm inflammation more quickly," she stated. "Targeting this mechanism could lead to safer treatments that restore immune balance without suppressing overall immunity" .

"This is the first study to map epoxy-oxylipin activity in humans during inflammation. By boosting these protective fat molecules, we could design safer treatments for diseases driven by chronic inflammation," said Professor Derek Gilroy, the study's corresponding author.

Professor Derek Gilroy, Division of Medicine at University College London

Why This Matters More Than Other Pain Treatments

What makes this discovery particularly exciting is that it targets the root cause of chronic inflammation rather than just masking symptoms. The drug used in the study, GSK2256294, is already suitable for human use, meaning it could potentially be repurposed relatively quickly for treating inflammatory flares in chronic conditions. This is especially important because, as Professor Gilroy noted, there are currently few effective therapies for preventing or managing acute flares in chronic inflammatory diseases .

The research also highlights why understanding the body's natural healing mechanisms matters. Rather than relying solely on drugs that suppress the entire immune system, this approach works with your body's own biology to enhance its natural ability to resolve inflammation. This could mean fewer side effects and better long-term outcomes for people living with chronic pain conditions.

"The pain of arthritis can affect how we move, think, sleep and feel, along with our ability to spend time with loved ones. That is why it is important that we invest in research like this, that helps us understand what causes and influences people's experience of pain," noted Dr. Caroline Aylott, Head of Research Delivery at Arthritis UK.

Dr. Caroline Aylott, Head of Research Delivery at Arthritis UK

What Happens Next?

The findings open the possibility of clinical trials to test sEH inhibitors as treatments for diseases such as rheumatoid arthritis and cardiovascular disease. Researchers are optimistic that this discovery could lead to new pain management options for people with arthritis and other chronic inflammatory conditions. The next phase will involve testing whether boosting epoxy-oxylipins can help prevent or slow disease progression in real-world patient populations .

For the millions of people living with chronic pain, this research represents a fundamentally different approach to treatment. Instead of asking "How can we suppress the immune system?" scientists are now asking "How can we help the body's natural healing mechanisms work better?" That shift in perspective could ultimately lead to safer, more effective treatments that address the underlying biology of chronic inflammation rather than just managing its symptoms.